1. Field of the Invention
The present invention relates to electronic blackboard devices capable of reading information written on a writing surface and printing the information on recording paper, and more particularly to an electronic blackboard device capable of reading and printing a plurality of colors.
2. Description of the Related Art
Conventionally, an electronic blackboard such as disclosed in JP-B-62-56000 is widely used in a meeting room of a private enterprise. In this case, the data recorded on the writing surface in a meeting can be printed as it is on general or heat-sensitive paper and it is unnecessary to take the trouble to write the data on a notebook. Data is written erasably with an aqueous marker on the writing surface of the blackboard, so that the data recorded on the writing surface is erasable with an eraser after use and the same writing surface is usable as a new writing surface. Not only the information written with the marker but also a chart pasted on the writing surface is readable.
However, the conventional electronic blackboard can read/print only in a monochromatic manner, so that information written with a red or blue marker other than a black one would be printed in black. Even when a chart using a plurality of different colors may be read, the chart would be printed only in a monochromatic manner. Thus, there is a strong demand for an electronic blackboard device capable of handling color printing.
The conventional color printing is usually performed in gradations and all toners of cyan (C), magenta (M), yellow (Y), and black (K or Bk) are mixed to form any particular color. Thus, even when data is written, for example, with a red monochromatic marker on the writing surface, there is a waste that all the C, M, Y and K toners are used to print the data.
Conventionally, data is written with a monochromatic marker on the writing surface of the blackboard or a photograph or a printed chart is pasted on the writing surface. In the latter case, the read chart is often printed in a high gradation/multi-color manner whereas in the former case, although data written with the marker can frequently and sufficiently be printed in a non-gradation/ monochromatic manner as mentioned above, there is a waste that all the C, M, Y and K toners are always used to print the data without discriminating the chart printing from the marker description/printing or vice versa.
Conventionally, there can be two areas concurrently on the same writing surface of the electronic blackboard, one in which data is written with a monochromatic marker and the other on which a photograph or a printed chart is pasted. In this case, the chart is read and printed often in a high gradation/multi-color manner whereas although the data written with the marker is printed often and sufficiently in a non-gradation and monochromatic manner, there is the waste that the C, M, Y and K toners are always used without discriminating the marker writing/ printing from the chart printing or vice versa.